A prober device is conventionally known as a device for inspecting electrical characteristics of respective semiconductor chips (semiconductor devices) prepared on a semiconductor wafer. A probe card is mounted to the prober device. With the probe card, the semiconductor chips on the semiconductor wafer are inspected one chip at a time. In the probe card, inspection probes are disposed so as to match a layout of all external terminals (input terminals and output terminals) of each semiconductor chip.
To inspect the semiconductor chips using the prober device, first, the probe card is positioned above one semiconductor chip on the semiconductor wafer. The probes are then brought in contact with all of the external terminals so that one probe corresponds to one external terminal. Electrical signals are then input into the input terminals of the semiconductor chip from the prober device. Electrical signals output from the output terminals of the semiconductor chip in accordance with the input signals are then read by the probe device, and signal waveforms of the output signals are compared with expected values stored in the probe device in advance. By this comparison, the qualities of the electric characteristics of the inspected chip are judged.
Meanwhile, in recent years, semiconductor chips are being further reduced in size and circuits are being made finer, and along with these trends, the external terminals provided in the chips are being made progressively narrower in pitch. Tip portions of the probes that contact the external terminals during inspection of the semiconductor chip must thus be made narrower in pitch. However, if just the magnitudes of the pitch of the tip portions of the probes are adjusted to match the pitch of the external terminals, the tip portions of adjacent probes may contact each other and cause a short circuit to occur between the tip portions and thereby lower the precision of inspection.
There has thus been proposed a method for forming probes with which the tip portions of the probes are made thinner than other portions by polishing by electric discharge machining after preparation of the probes to prevent mutual contact of adjacent probes and achieve narrowing of the pitch of the tip portions of the probes.